This invention relates to a process for the production of radically post-crosslinked polymers. In a first stage of the process according to the invention, one or more special acrylic or methacrylic acid derivatives based on naturally occurring oils is/are reacted with aromatic and/or aliphatic isocyanates and, in a second stage, the polyurethanes (a*) thus obtained are subsequently subjected to radical post-crosslinking in the presence of a radical initiator (b), with the proviso that a combination of the compounds (a*) with one or more compounds (c) selected from the group of diallyl phthalates is used in the second stage.
The use of radiation curing in the coating industry for producing high-quality coating materials is known from the prior art. In radiation curing, olefinically unsaturated compounds (monomers, oligomers, polymers, prepolymers), i.e. compounds containing Cxe2x95x90C double bonds as structural elements, are cured by exposure to high-energy radiation, for example UV light or electron beams. The actual radiation curing process is sometimes preceded by physical drying.
It is also known that particularly high-quality coatings are obtained in radiation curing when the olefinically unsaturated starting compounds used contain polyurethane groups as further structural elements. Unsaturated radiation-curable urethane acrylates are known from Manfred Bock (Ed. Ulrich Zoril), xe2x80x9cPolyurethane fxc3xcr Lacke und Beschichtungenxe2x80x9d, Hannover 1999, pages 73-74.
U.S. Pat. No. 3,979,270 describes a process for the curing of amine derivatives of reaction products of acrylated epoxidized soybean oil in which curing is carried out by high-energy radiation.